1. Field of the Invention
The present invention relates in general to the field of information handling system power supplies, and more particularly to a system and method for power good monitor for multiple information handling system power supplies.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
One way that information handling systems provide flexibility to accomplish a variety of tasks is that they are built from a variety of processing components. Selection of appropriate processing components, such as CPUs, hard disk drives, embedded controllers, etc . . . , allows an end user to achieve a desired performance level for a given cost. The result is that an information handling system can have a wide variety of components, each with its own power supply requirements. To meet the power needs of processing components, an information handling system often includes power supplies with multiple voltage levels and varied power capabilities. In some instances, information handling systems, such as portable system, use power rail switches to further partition power supply wells. Using power rail switches provides a “subset” power source that aids portable information handling system power management and provides increased flexibility in available power supply sources within a system with reduced cost and footprint.
One difficulty with the use of power rail switches to partition power supply is that each switched power rail should be monitored to ensure that it remains within operating limits. Typically, an information handling system monitors power rails to generate a combined “Power Good” feedback signal that indicates the power rails are working properly. If a failure of any power rail is detected, the Power Good feedback signal is terminated so that a power manager of the information handling system, typically found in an embedded controller, knows that one or more power rails needed for operation of the information handling system are not operational and can take appropriate corrective steps. Failure to detect defective power rails may violate power sequencing specifications, leading to an extreme overheating of integrated circuits that receive power from a failed power rail. Without a failure indication, control logic in the embedded controller, such as a PMC, would continue to enable power delivery to partially-powered target integrated circuits causing severe backdrive and overheating of the integrated circuit. Extreme heat from partial power applied to an integrated circuit may result in catastrophic failure to the information handling system. Although the application of partial power from a switched power rail failure can result in catastrophic damage, switched power rails often remain unmonitored due to the expense of “power good”solutions. Generally, monitoring of non-switched rails by DC-DC regulators or comparator integrated circuits is relied upon to detect and correct power system failures.